Color kinescopes



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June 11, 1957 F. VAN HEKKEN ETAL 2,795,718

COLORA KINEscoP'Es Filed Aug. 18, 1954 2 sheets-sheet 1 if /f if' 1' iif g' f ifa June 11, 1957 F. VAN HEKKEN ErAL 2,795,718

COLOR KINESCOPES Filed Aug. 18, 1954 2 Sheets-Sheet 2 1NVENTOR5 ijnitedStates Patent coLoR KnsnscorEs Application August 18, 1954, Serial No.450,733

13 Claims. (Cl. 313-85) Lancaster, Corporation of America, a cor- Thisinvention relates to improvements in color-kinescopes and other (e. g.camera, radar, and stereoscopic) cathode-ray (CR) tubes of the kindcontaining an apertured mask through which beam-electrons pass in theirtransit to the electron-sensitive mosaic target-surface of a nearbyscreen.

In cathode-ray tubes of the various kinds to which the invention-isapplicable, the accuracy with which the beamelectrons strike theindividual screen-areas depends, in large measure, upon the accuracywith which the maskapertures are aligned with said screen-areas. Thus,in the case of a color-kinescope, should the mask expand by reason ofthermal effects occasioned by the impact thereon of the electron-beam,or beams, then the beam-elec- Fig. 4 is an elevational View of one ofthe links or hinges of the temperature compensated mask;

Fig. 5 is a fragmentary View, partly in section, of the mask and itssupports;

, Fig. 6 is a fragmentary View, partly in section, showing analternative form of mask-supporting hinge r lever;

Fig. 7 is a plan view and Fig. 8 an elevational view of l a mask havinga hinged temperature-compensating border, .and

Figs. `9 and 10 are fragmentary sectional views of other forms of hingedmask-boarders, within the invention.

ln Fig. 1 the invention is shown as applied to a 3-gun tri-colorkinescope of the so-called masked-target dotscreen variety wherein thered (R) blue (B) and green (G) phosphor dots (see Fig. 2) are arrangedin a hexagonal mosaic pattern on the rear or target surface 1 of a glassscreen-plate 3. This electron-sensitive color-screen may be of anydesired shape e. g. circular or rectangular) and curvature (e. g.spherical, cylindrical or at). In the instant case it is in the form ofa circular section of a spherical shell and comprises the front end orwindow of a metal envelope of more or less conventional form anddimensions. Alternatively, the color screen may trons, or some of them,may impinge upon color-areas"- Y vention is to provide an improvedmethod of and means for maintaining the apertures of a shadow-mask inalignment with the lelemental areas of a mosaic Vtype screen over a widerange of operating temperatures and this too without resort to the useof auxiliary mask-supporting carriages and bearings or costly (lowexpansion) materials for the mask and/or its supports.

Stated generally, the foregoing and related objects are achieved inaccordance with the present invention by the provision of a mask havinga marginal edge portion or portions comprising a movable link, hingeorlever (frequently hereinafter referred to as a hinge) which, whenactuated by the force of expansion (or contraction) of the maskmaterial, moves the apertured scanned-area of the mask towards (or awayfrom) the screen along lines which coincide, substantially, with thedeflection angle of the beam, or beams, at each aperture. (The termdetlection angle, as applied to a S-beam tube, is the angle subtended bya line drawn from any point on the screen, or its mask, along a medianline of the beam-paths to the central axis of the tube.) The expansionor temperature compensating hinge may be integral with the mask, andthis structure carried byaframe which in turn may be removably supportedon fixtures or protuberances provided for the ptupose on the innersurface of the cap or other part of the envelope.

The invention is described in greater detail in connection with theaccompanyingv two sheets of drawings, wherein:

Fig. lis a longitudinal sectional view of a 3-gun tricolor kinescope ofthe shadow-mask dot-screen varietyr containing a temperature compensatedmask constructed in accordance with the principle of the invention;V

Fig. 2 is a fragmentary rear-elevational view of the screen-unit of. thecolor-kinescope ofy Fig. 1, showing a conventional (hexagonal) patternof mask-apertures and color-phosphor dots;

Fig. 3`is a front elevational view of the mask of the screen-unit ofFigs. 1 and 2, showing a six-point distribution of the mask-supports;

comprise a at glass plate, not shown, mounted behind the window.

`The mask 7 for the mosaic screen may be formed of any suitable materialhaving a positive temperature coeicient of expansion. Thus it maycomprise a thinmetal (e. g. iron, steel or copper) member, or it may bemade of perforated glass which has been metallized or otherwise treatedto render its surface conducting.

Where, as in Fig. 1, the mosaic screen pattern (RBG)l is laid downdirectly on the concave inner surface 1 v of the face plate 3, the mask7 is appropriately curved so that it conform generally with said concavetargetsurface. mask are arranged in the same (e. g. hexagonal)systematic pattern-as` the phoshor triads RBG on the mosaic screenl,there being one mask-aperture for each triad. Ags-is conventional, thered, blue and green electron-guns `9r, 9b, 9 g are arrangeddelta-fashion about the central axisr'x-x lof the envelope, in the glassneck 11. With the guns and mask-apertures thus arranged the threescanning beams pass through-the tubes plane-ofdeection A-A with theirkcenters equally spaced from each other at a common distance-from thetube axis and converge adjacent. to the surface of the mask Where theirpaths cross and proceed to the respective color areas on the screen. l

The plane-of-deflection, referred to in the precedingl paragraph is heredefined as the plane in which the axis of each deflected beam, whenextended rearwardly, intersects'` the axis of origin of that beam. Whenthe three beams are undeflected, i. e. when they are directed to thecenter of the screen-unit, the plane-of-deflection crosses the centralaxis x-x of the tube at'or near the center of the deflection yoke 13, asindicated by' the lineA-A.

mask 7 is supported at a number (in this case, six) of places about itsperiphery by hinge elements 15 (see Fig. 4) which are secured, as bywelding, at one end to theimask andat the opposite end to a rigid metalannulus or'frame 17. The frame 17 and hence the mask 7 and its hinges15` are in turn supported upon metal pins 19 A which extend inwardlyfrom the inner surface of the metal sidewalls 4of the cap 21` of thetube and are seated in V-.grooves 23 in smallmetal blocks Z5 on theouter surface ofthe masks frame 17.

ln one successful embodiment of the invention, wherein six hinges 15provided the requisite temperature-com- Peiftented June 1,1, 1 957A Theapertures 7a in the scanned area 7s of the pensating hinging movementsfor a rectangular maskhaving a 2l" diagonal, the hinge members 15 wereof duplicate construction and were formed of thin (0.006" Inportion 15bsecured adjacent to its outer edge 15e (by similar welds, not shown) tothe edge of themask 7. The hinging action of these metal supports 15 wasconfined to the area of the bends 15d and 15e in the metal by vnarrowslits 15j, 15g, respectively, along each bend and byreinforcing'embossments 15h between said slits.

It will be observed upon inspection of Fig. l that the surface or plane15b of the link portion of the masksupporting hinge 15 forms an angle of90 with respect to a line y-y drawn from `its upper bend 15a' t0 themid-point of the tubes plane-of-dellection A-A. That is to say, when themask is cold, the inclined surface 15b is normal to a line v-y extendingtherefrom to the centerof-dellection of the beam (or beams) at thatpoint. With the hinge or link members 15 thus arranged, their hingingaction (when subjected to the force of expansion of the heated maskmaterial) is such that each apertured area in the mask moves toward thescreen along a substantially straight path which coincides with a linedrawn from the center of detiection to the phosphor triad associatedwith that particular aperture. Thus the alignment between the maskapertures 7a and the elemental areas (RB and G) on the target surface ofthe mosaic screen is maintained substantially irrespective of theoperating temperature of the mask.

it is apparent that the invention is not Ilimited in its usefulapplication to the particular form or kind of hinge in the mask issupported for slidable movement on one arm'27a and the force P (ofexpansion of the mask material) is applied to the other arm 2711,thefulcrum F being at the apex of the angle formed by the two arms.

Instead of making the temperature compensating hinges inthe form ofseparate pieces and welding them in place they may be formed integralwith the mask, as shown, by Way of example, in Figs. 7 to 10 inclusive.

In Figs. 7 and 8, the centrally located apertured targetportion of themask, which is here designated 39, is in the form of a rectangular(instead of circular) portion of a spherical shell and is provided withVan integral temperature compensating border or inner-rim portion 33made up of a multiplicity of circumferentially spaced, rigid, linkelements 35 which have inclined surfaces 37 connecting the aperturedtarget area 39 of the mask with its upstanding mask-supporting outer-rimportion 41. Here, as before, the inclined surfaces 37 of the linkportions 35 of the mask-supporting hinge preferably form angles of 90with respect to lines y-y drawn from their centers to the mid-point ofthe tubes plane-of-deection (A-A, Fig. l). Also, as before described,the hinging action is conned to the area of the flexible bends 43 and 45in the metal at the opposite ends of each of the 'rigid link elements35. 1

In reducing the above described embodiment of the invention to practicethe apertured part 39 of the mask 31 and its open-work border 33 wereformed in a single at sheet of thin-metal by a conventional etchingprocess and the sheet then deepdrawn into its ultimate shape with theaid of a die, not shown.

In the embodiments of the inventonabove described in connection withFigs. 7 and 8 the required rigidity of the link elements 35 was achievedby making the body of each link wider than its terminal portions. Thesame v result has been achieved by making the links of uniform 4 width,as shown at 51 in Fig. 9, and reinforcing them, each by an embossment53.

In all of the embodiments of the invention thus far described the hingesor links between the target area of the mask and its supporting rim areseparated one from the others by intervening spaces. While this isdesirable (because of the resulting saving in weight), it may add to thecost of the unit and, in any event, is not always essential to thepractice of the invention. Thus, as shown in Fig. l0, the rigid elementsof the hinge may comprise embossments 55 pressed in an imperforateborder 57 surrounding the target areas of the mask, which is heredesignated 59.

As previously indicated, the embossments 15h (Fig. 4), 53 (Fig. 9), 55(Fig. l0) serve to reinforce the innerrim portion of the hinge and thusto confine its pivotal movements to the area of the exible bends (15d,15e, Fig. 4;V 43, 45, Figs. 7-10) in the metal. Reinforcement orstitfening of the inner-rim or body of the hinge may also be achieved bythickening the metal (e. g. by electroforrning) of which said part orparts are formed, or in other ways. For example by the use of discretemetal bars or ribs, not shown. Where stiifening ernbossments areemployed, the embossrnents may assume various forms. That is to say,they are not necessarily of the crossed pattern shown at 15h, Fig. 4, orof the parallel-line pattern shown at S3, Fig. 9; 55 Fig. l0, but maycomprise mere dot-'like embossments, not shown.

From the foregoing specification it should now be apparent that thepivotal mask-supporting means of the present invention provides a simpleyet effective means for maintaining the apertures of a shadow-mask inalignment with the elemental areas of a mosaic screen over a wide rangeof operating temperatures.

What is claimed is: Y

l. A cathode-ray tube comprising an evacuated envelope having alongitudinal axis and containing means for generating at least oneelectron-beam, a mask extending across said axis in a position to bescanned by said beam, said mask being constituted essentially of amaterial that expands when subjected to heat generated as an incident tothe impact of beam-electrons thereon and containing a multiplicity ofapertures through which beam-electrons pass along v substantiallystraight paths which form variousV deflection rangles with saidlongitudinal axis as determined by the instantaneous position of saidbeam during its scanning movements, a screen having anelectron-sensitive mosaictarget-snrface spaced from said maskvwith theelemental areas of which said mosaic is comprised aligned with respectto the apertures in said mask, and pivotal means cooperativelyassociated with said mask for supporting said mask Within said envelopeand for causing each apertured area of said mask to move along saidstraight paths in response to the expansion of said mask material whenit is subjected to heat generated as an incident to the impact of beamelectrons thereon.

2. The invention as set forth in claim l and wherein said last mentionedmeans comprises hinge means tlexibly connected at one end to the edge ofsaid mask and ilexibly connected at its opposite end to a support on theinterior of said envelope.

3. The invention as set forth in claim 2 wherein said link member isdisposed along an axis that formsan angle of approximately 90 withrespect to a straight line drawn from said one end of said link to thepoint whereat said straight beam-paths intercept the longitudinal axisof said tube.

4. A mask comprising a substantially rigid marginal edge-portion forattachment to a support, a centrally located apertured target-portionconstituted essentially of a temperature-sensitive material, and bingemeans responsive to expansion and contraction of saidtemperature-sensitive material `connecting said apertured targetportionto said marginal-edge portion.

5. The invention as set forth in claim 4 and wherein said hinge meanscomprises a substantially rigid link member iiexibly connected at itsinner and outer extremities to said target and marginal-edge portions,respectively.

6. A mask comprising a centrally located apertured target-portionsubstantially in the form of a section of a spherical shell andconstituted essentially of a material that expands when subjected toheat generated by electron-bombardment, an inner-rim portion connectedto said spherical target portion by a exible bend in said material andinclined inwardly with respect to the concave surface of said sphericalshell, and an outer-rim portion connected by a second tiexible bend insaid material to the outer edge of said inner-rim, whereby saidinner-rim comprises the connecting link and said first and second bendscomprise the pivots of a hinge capable of translating the force ofexpansion of said spherical target portion into a movement in adirection away from its center-of-curvature.

7. The invention as set forth in claim 6 and wherein said mask consistsessentially of a single piece of thin metal and said inner-rim portionof said thin metal contains a plurality of spaced-apart strengtheningembossments disposed between said tirst and second exible bends in themetal, whereby the pivotal movements of said hinge are connedsubstantially to said flexible bends.

8. The invention as set forth in claim 7 and wherein said inner-rimportion of said mask contains perforations in the metal between adjacentones of said strengthening embossments.

9. A mask comprising a centrally located apertured target portionconstituted essentially of a material that expands when subjected toheat, an inner rim portion and an outer-rim portion, rst exible meansresponsive to expansion of said material disposed between said targetportion and said inner-rim portion, and second flexible means disposedbetween said inner-rim portion and said outer-rim portions.

10. The invention as set forth in claim 9 and wherein the inner-rimportion of said mask is constituted of the same material of which saidtarget portion is comprised and said first and second flexibleconnecting means comprise discrete flexible areas in said material.

11. A mask constituted essentially of thin metal and comprising anouter-rim portion for attachment to a support, an inner-rim portionconnected to said outerrim by a bend in said thin-metal and a centralapertured target portion connected to said inner-rim by a second bend inthe thin-metal.

12. A mask constituted essentially of thin metal and comprising acircular outer-rim portion for attachment to a support, a frusto-conicalinner-rim portion connected to said outer-rim by a bend in saidthin-metal and a central traget-portion in the form of a circularsection of a spherical shell containing a multiplicity of systematicallyarranged apertures and connected to said innerrim by a second bend insaid thin-metal.

13. A mask constituted essentially of thin metal and comprising arectangular outer-rim portion for attachment to a support, afrusto-pyramidal inner-rim portion connected to said rectangularouter-rim on each of its sides by a bend in said thin metal, and acentral electrontarget portion in the form of a rectangular section of acurved surface containing a multiplicity of systematically arrangedapertures and connected to said inner-rim on each of its sides by asecond bend in said thin-metal.

References Cited in the le of this patent UNITED STATES PATENTS Re.23,735 Olson Nov. 10, 1953 2,546,828 Levy Mar. 27, 1951 2,611,100Faulkner et al. Sept. 16, 1952 2,682,620 Sanford June 29, 1954

